This application is a national stage application of International Application Number PCT/EP00/08433 filed on Aug. 30, 2000 which claims priority to German Application No. 19942509.4 filed on Sep. 7, 1999.
1. Field of the Invention
The invention relates to a method and a device for the supply of electrical loads in or on a pneumatic device with electrical power energy, the pneumatic device being connected by way of a pneumatic line with a source of pressure.
2. Description of the Prior Art
For the control of pneumatic equipment, such as valve arrangements, cylinders, drives and the like, there is on the one hand the requirement for the supply of compressed air by way of a pneumatic line and on the other hand for electrical supply lines for the supply of electrical power energy and of electrical control signals and furthermore possibly return lines for the return of sensor signals. If a plurality of control devices, such as valves, are arranged on one pneumatic device, together with a plurality of sensors, there is a corresponding increase in the number of electrical lines, safety which frequently means that there is a somewhat chaotic arrangement of lines involving high costs for the installation, servicing and repair of such equipment.
The German patent publication 19,526,459 discloses the operation of a bus station valve station comprising a plurality of valves by way of a bus line, by way of which it is also possible for sensor return signals to be passed, but there is here a requirement for additional electrical power lines and the pneumatic line so that in this case the complexity of installation is substantial.
Although the German patent publication 3,147,399 A1, the German patent publication 3,209,189 A1 and the German patent publication 4,126,403 C2 disclose the transmission of control or sensor data ultrasonically through metallic tube supply network, the power energy is not so transmitted and furthermore such method is not applicable to pneumatic lines, which conventionally consist of plastic material
Accordingly one object of the present invention is to provide a method and a device by means of which the number of connecting lines leading to a pneumatic device to be controlled may be substantially reduced and installation may be simplified.
The advantage of the device in accordance with the invention is more particularly that using the pneumatic line, which is present in any case it is simultaneously possible for power energy to be transmitted for electrical loads in the pneumatic device so that the no separate lines are required for this purpose. In this case transmission is by way of the gaseous medium or, respectively, conduction is by means of acoustic waves, microwaves, changes in pressure or by means of flow energy of the gaseous medium subject to pressure. For this reason the transmission of energy is possible in the case of conventionally employed plastic lines. The conversion into electrical power energy is performed directly on or in the pneumatic device.
In accordance with a further preferred development the pressure of the gaseous medium in the pneumatic line is utilized for driving a microturbine with an electrical generator, that is to say the flow energy of the gaseous medium under pressure is directly converted in or at the pneumatic device into electrical power energy.
In an alternative design of the invention the acoustic waves or changes in pressure are converted by means of the piezo effect or by capacitive or inductive conversion methods at least partially into electrical power energy in the pneumatic device. For the conversion of the acoustic waves or changes in pressure use is preferably here made of a piezoelectric, capacitive or inductive converter or an oscillating piston arrangement. Such a converter or an oscillating piston arrangement is also preferably provided in a control and/or data receiving means, connected by way of the pneumatic line with the pneumatic conversion of the electrical energy into acoustic waves to be supplied to the pneumatic line or into pressure changes.
It is a advantage for the transmission of control and/or sensor signals between the electronic control and/or data receiving means and the pneumatic device to be by way of the pneumatic line using acoustic signals, microwaves or changes in pressure. For this purpose preferably different frequencies and/or signal sequences and/or modulation and/or pressure pulse sequences are provided, the transmission taking place preferably bidirectionally in order to be able to return sensor signals as well.
For the transmission of such control and sensor signals the control and/or data receiving means and the pneumatic device are preferably provided with at least one first converter for the conversion of electrical signals into acoustic signals or pressure changes and with at least one second converter for the conversion of the acoustic signals or pressure changes into electrical signals. For the bidirectional data transmission both the control and/or data receiving means and also the pneumatic device is provided with a first converter and with a second converter, one first converter and one second converter being designed in the form of a combined bidirectional converter if desired. For this purpose it is possible to employ more particularly piezoelectric or however also inductive or capacitive converters.
The converters for the supply of power energy may be advantageously identical to the converters for the conversion between acoustic signals or pressure changes and electrical control and/or sensor signals, since with the performance of this double function better utilization is possible.
In an alternative design the transmission of control and/or sensor signals between the electronic control and/or data receiving means and the pneumatic device may also takes place in a wireless manner and more particularly by radio or infrared signals or by way of optical guide arranged in or on the pneumatic line or integrated in same in the latter case the control and/or data receiving means and the at least one pneumatic device will preferably be provided respectively with an optical transmitter and/or a optical receiver.
In order to make the supply voltage available continuously, for instance in the case of an energy requirement which is increased for a short time, it is advantageously possible to provide a storage means and more particularly a capacitor or a storage cell, for the storage of the electrical power energy produced in or at the pneumatic device.
A converter which is more especially in the form of a microcomputer in or on the pneumatic device preferably serves for the conversion of the transmitted signals into control signals for at least one control means, as for example a valve, in the pneumatic device and/or for conversion of sensor signals into signals to be transmitted.
The control and/or data receiving means is preferably designed in the form of a bus station connected with a data bus. In this respect a plurality of pneumatic devices may be connected with this bus station by way of pneumatic lines directly or by way of branch lines.
In the case of systems of large size it is possible furthermore for several bus stations to be connected with the data bus, which are respectively connected with at least one pneumatic device.
The at least one converter and the means for making the electrical power energy available are preferably integrated in the pneumatic device so that the arrangements are compact, which for complete installation only have to be connected by way of a single pneumatic line.
Working examples of the invention are illustrated in the drawings and will be explained in the following description in detail